Within Session SSVEP#

This Example shows how to perform a within-session SSVEP analysis on the MAMEM dataset 3, using a CCA pipeline.

The within-session evaluation assesses the performance of a classification pipeline using a 5-fold cross-validation. The reported metric (here, accuracy) is the average of all fold.

# Authors: Sylvain Chevallier <sylvain.chevallier@uvsq.fr>
#
# License: BSD (3-clause)

import warnings

import matplotlib.pyplot as plt
import seaborn as sns
from sklearn.pipeline import make_pipeline

import moabb
from moabb.datasets import Kalunga2016
from moabb.evaluations import WithinSessionEvaluation
from moabb.paradigms import SSVEP
from moabb.pipelines import SSVEP_CCA


warnings.simplefilter(action="ignore", category=FutureWarning)
warnings.simplefilter(action="ignore", category=RuntimeWarning)
moabb.set_log_level("info")

Loading Dataset#

Load 2 subjects of Kalunga2016 dataset

Choose Paradigm#

We select the paradigm SSVEP, applying a bandpass filter (3-15 Hz) on the data and we keep only the first 3 classes, that is stimulation frequency of 13Hz, 17Hz and 21Hz.

paradigm = SSVEP(fmin=10, fmax=40, n_classes=3)

Create Pipelines#

Use a Canonical Correlation Analysis classifier

interval = dataset.interval
freqs = paradigm.used_events(dataset)

pipeline = {}
pipeline["CCA"] = make_pipeline(SSVEP_CCA(n_harmonics=3))

Get Data (optional)#

To get access to the EEG signals downloaded from the dataset, you could use dataset.get_data(subjects=[subject_id]) to obtain the EEG under MNE format, stored in a dictionary of sessions and runs. Otherwise, paradigm.get_data(dataset=dataset, subjects=[subject_id]) allows to obtain the EEG data in scikit format, the labels and the meta information. In paradigm.get_data, the EEG are preprocessed according to the paradigm requirement.

# sessions = dataset.get_data(subjects=[3])
# X, labels, meta = paradigm.get_data(dataset=dataset, subjects=[3])

Evaluation#

The evaluation will return a DataFrame containing a single AUC score for each subject and pipeline.

overwrite = True  # set to True if we want to overwrite cached results

evaluation = WithinSessionEvaluation(
    paradigm=paradigm, datasets=dataset, suffix="examples", overwrite=overwrite
)
results = evaluation.process(pipeline)

print(results.head())
Kalunga2016-WithinSession:   0%|          | 0/2 [00:00<?, ?it/s]
Kalunga2016-WithinSession:  50%|█████     | 1/2 [00:09<00:09,  9.55s/it]

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 14%|█████▍                                 | 315k/2.27M [00:00<00:02, 858kB/s]

 38%|██████████████▎                       | 855k/2.27M [00:00<00:00, 1.91MB/s]

 87%|████████████████████████████████     | 1.97M/2.27M [00:00<00:00, 4.41MB/s]

  0%|                                              | 0.00/2.27M [00:00<?, ?B/s]
100%|█████████████████████████████████████| 2.27M/2.27M [00:00<00:00, 10.5GB/s]


  0%|                                              | 0.00/2.13M [00:00<?, ?B/s]

  1%|▏                                     | 13.3k/2.13M [00:00<00:20, 102kB/s]

  4%|█▋                                    | 94.2k/2.13M [00:00<00:06, 316kB/s]

 11%|████▍                                  | 241k/2.13M [00:00<00:03, 531kB/s]

 19%|███████▍                               | 404k/2.13M [00:00<00:02, 659kB/s]

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 39%|███████████████▏                       | 829k/2.13M [00:01<00:01, 912kB/s]

 51%|██████████████████▉                  | 1.09M/2.13M [00:01<00:00, 1.05MB/s]

 63%|███████████████████████▏             | 1.34M/2.13M [00:01<00:00, 1.12MB/s]

 74%|███████████████████████████▏         | 1.56M/2.13M [00:01<00:00, 1.13MB/s]

 82%|██████████████████████████████▎      | 1.74M/2.13M [00:01<00:00, 1.07MB/s]

 94%|██████████████████████████████████▌  | 1.99M/2.13M [00:02<00:00, 1.13MB/s]

  0%|                                              | 0.00/2.13M [00:00<?, ?B/s]
100%|█████████████████████████████████████| 2.13M/2.13M [00:00<00:00, 7.85GB/s]

Kalunga2016-WithinSession: 100%|██████████| 2/2 [00:23<00:00, 11.90s/it]
Kalunga2016-WithinSession: 100%|██████████| 2/2 [00:23<00:00, 11.55s/it]
      score      time  ...  pipeline                  codecarbon_task_name
0  0.333333  0.001147  ...       CCA  9b6ff55e-36e1-4f27-adc0-bacbc643d908
1  0.335556  0.001058  ...       CCA  b1a89f36-4794-44e5-a3f0-9cfb3fa815ba

[2 rows x 11 columns]

Plot Results#

Here we plot the results, indicating the score for each subject

plt.figure()
sns.barplot(data=results, y="score", x="session", hue="subject", palette="viridis")
plot within session ssvep
<Axes: xlabel='session', ylabel='score'>

And the computation time in seconds

plt.figure()
ax = sns.barplot(data=results, y="time", x="session", hue="subject", palette="Reds")
ax.set_ylabel("Time (s)")
plt.show()
plot within session ssvep

Total running time of the script: (0 minutes 25.518 seconds)

Estimated memory usage: 322 MB

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